Miniature implantable connectors

ABSTRACT

The invention discloses methods of making electrical connections in living tissue between an electrically conductive wire and an implantable miniature device. The device may either stimulate muscles or nerves in the body or detect signals and transmit these signals outside the body or transmit the signals for use at another location within the body. The device is comprised of an electrically insulating or electrically conductive case with at least one electrode for transmitting electrical signals. The electrodes and the wire-electrode connections are protected from the aggressive environment within the body to avoid corrosion of the electrode and to avoid damage to the living tissue surrounding the device.

[0001] This application claims the benefit of U.S. Provisionalapplication No. 60/299,106, filed Jun. 18, 2001.

FIELD OF THE INVENTION

[0002] This invention relates to a prosthetic medical device andmethods, and more particularly to methods of connecting electricalconducting wires to a miniature implantable device to minimize risk tothe living tissue during and after surgery.

BACKGROUND OF THE INVENTION

[0003] Neurological disorders are often caused by neural impulsesfailing to reach their natural destination in otherwise functional bodysystems. Local nerves and muscles may function, but, for variousreasons, such as injury, stroke, or other cause, the stimulating nervesignals do not reach their natural destination. For example, paraplegicand quadriplegic animals have intact nerves connected to functioningmuscles and only lack the brain-to-nerve link. Electrically stimulatingthe nerve or muscle can provide a useful muscle contraction.

[0004] Further, implanted devices may be sensors as well as stimulators.In either case, difficulties arise both in providing suitable, operablestimulators or sensors which are small in size and in passing sufficientenergy and control information to or from the device, with or withoutdirect connection, to satisfactorily operate them. Miniature monitoringand/or stimulating devices for implantation in a living body aredisclosed by Schulman, et al. (U.S. Pat. No. 6,164,284), Schulman, etal. (U.S. Pat. No. 6,185,452), and Schulman, et al. (U.S. Pat. No.6,208,894).

[0005] It must be assured that the electrical current flow does notdamage the intermediate body cells or cause undesired stimulation.Anodic or cathodic deterioration of the stimulating electrodes must notoccur.

[0006] In addition, at least one small stimulator or sensor disposed atvarious locations within the body may send or receive signals viaelectrical wires.

[0007] The implanted unit must be sealed to protect the internalcomponents from the body's aggressive environment. If wires are attachedto the stimulator, then these wires and the area of attachment must beelectrically insulated to prevent undesired electric signals frompassing to surrounding tissue.

[0008] Miniature stimulators offer the benefit of being locatable at asite within the body where a larger stimulator cannot be placed becauseof its size. The miniature stimulator may be placed into the body byinjection. The miniature stimulator offers other improvements overlarger stimulators in that they may be placed in the body with little orno negative cosmetic effect. There may be locations where theseminiature devices do not fit for which it is desired to send or receivesignals. Such locations include, but are not limited to, the tip of afinger for detection of a stimulating signal or near an eyelid forstimulating blinking. In such locations, the stimulator and itsassociated electronics are preferably located at a distance removed fromthe sensing or stimulating site within the body; thus creating the needto carry electrical signals from the detection or stimulation site tothe remote miniature stimulator, where the signal wire must be securelyfastened to the stimulator.

[0009] Further, the miniature stimulator may contain a power supply thatrequires periodic charging or require replacement, such as a battery.When this is the case, the actual stimulation or detection site may belocated remotely from the stimulator and may be located within the body,but removed a significant distance from the skin surface. By having theability to locate the miniature stimulator near the skin while thestimulation site is at some distance removed from the skin, theminiature stimulator and its associated electronics can be moreeffectively replaced by a surgical technique or more efficientlyrecharged through the skin by any of several known techniques, includingthe use of alternating magnetic fields. If the electronics package isreplaced surgically, then it is highly desirable to have the capabilityto reconnect the lead wires to the miniature stimulator via an easy,rapid and reliable method, as disclosed herein.

SUMMARY OF THE INVENTION

[0010] The instant invention relates to apparatus and methods forconnecting an electrically conductive wire to a miniature, implantablestimulator. The stimulator case is comprised of electrically insulatingmaterials such as plastic or ceramic. The plastic may be epoxy,polycarbonate, or plexiglass.

[0011] The ceramic may be alumina, glass, titania, zirconia,stabilized-zirconia, partially-stabilized zirconia, tetragonal zirconia,magnesia-stabilized zirconia, ceria-stabilized zirconia,yttria-stabilized zirconia, or calcia-stabilized zirconia. There is atleast one electrically conductive electrode for conducting electricalsignals. The materials comprising such electrically conductive parts areselected to reduce or eliminate damage due to corrosion from the tissueenvironment surrounding the miniature stimulator, and also to avoiddamage to the tissue, for example, not being toxic or having sharpcorners that can damage the tissue.

[0012] The electrical connection between the electrically conductivecase parts and the electrically conductive wires is accomplished byseveral methods, including the use of crimping, welding, threading, orinterlocking by bayonet means, snap-on means, screwing-on means, or pinmeans. The wire may also be secured to the electrode in a variety ofnovel ways, including, compression fits between the cap and electrodethat secure the wire by compression fit.

[0013] The electrode may be either a male pin or a female receptorconfiguration. Apparatuses for insulating the electrode from the bodyand for making attachment of a wire to the electrode are disclosed. Someof these approaches to making safe and secure electrical connectionsbetween and electrode and wire include bayonet mounting of the cap tothe electrode, crush lips to secure the wire between the cap and theelectrode, and spade clips to allow quick and secure attachment of thewire to the electrode.

[0014] In any of these approaches to making a secure and safe connectionof wire to connector attachment, the entire connection area and wiremust be electrically insulated from the body. Placing a flexibleinsulating boot over the entire stimulation wire connection accomplishesthis. The insulating boot is preferably held in place with at least oneof several methods, including ties, C-clips, silicone adhesive or atight fit with or without a securement ridge.

[0015] Each connection mechanism allows for the use of a wire with atleast one separate element, each of which may carry an independentelectrical signal. Further multi-connector slip cap or feedthroughapparatuses are disclosed which allow multiple independent electricalconnections to be made in a single maneuver during surgery.

[0016] This invention offers a variety of configurations to the surgeon,both pre-surgery and during surgery. Changes may be made to theconfiguration to accommodate necessary modifications during surgery andduring secondary surgeries at a later time. Corrosion is prevented orsignificantly reduced by the proper selection of materials and the useof an electrically insulating boot in combination with secure attachmentmethods.

OBJECTS OF THE INVENTION

[0017] It is an object of the invention to provide an implantableminiature stimulator having at least one electrode.

[0018] It is an object of the invention to provide a method ofconnecting at least one wire to a miniature stimulator in a body.

[0019] It is an object of the invention to increase the ease and safetyof a surgeon making electrical connections for in vivo application of aminiature implantable stimulator.

[0020] It is an object of the invention to connect the electrode of aminiature implantable stimulator in a secure, safe and rapid fashion toelectrical wires.

[0021] It is an object of the invention to electrically insulate theelectrode of an implantable miniature stimulator that is connected to anelectrical wire from the body environment in which it is implanted.

[0022] Other objects, advantages and novel features of the presentinvention will become apparent from the following detailed descriptionof the invention when considered in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1 illustrates a perspective view of the miniature stimulatorwith a threaded connector and nut.

[0024]FIG. 2 illustrates a perspective view of the miniature stimulatorwith a bayonet connector and nut.

[0025]FIG. 3 illustrates a perspective view of the miniature stimulatorwith a pin connector and nut.

[0026]FIG. 4 illustrates a perspective view of the smooth nut with aflare nut cap.

[0027]FIG. 5 is a cross-section through the flare nut wire insertion.

[0028]FIG. 6 is a cross-sectional view of the smooth cap with flareinsertion.

[0029]FIG. 7 is a longitudinal section through the protective nutshowing an offset mounting hole.

[0030]FIG. 8 is a cross-section through the protective nut showing theoffset mounting hole.

[0031]FIG. 9 illustrates a stimulator with a hole and pin electrode.

[0032]FIG. 10 illustrates a stimulator with a hole and pin electrode andan electrode plug.

[0033]FIG. 11 is a longitudinal cross-section of a threaded holeelectrode with plug.

[0034]FIG. 12 is a longitudinal cross-section of a threaded pinelectrode with nut.

[0035]FIG. 13 is a longitudinal cross-section of a threaded pinelectrode with nut and spade connector.

[0036]FIG. 14 illustrates a spade connector.

[0037]FIG. 15 illustrates a spade connector attached to a wire.

[0038]FIG. 15A illustrates a detailed section of the crimp of FIG. 15.

[0039]FIG. 15B illustrates a detailed section of an alternate crimp ofFIG. 15.

[0040]FIG. 16 is a longitudinal cross-section of an electrode hole witha plug and crush lip.

[0041]FIG. 17 illustrates a C-clamp.

[0042]FIG. 18 illustrates a pin electrode with a wire inserted.

[0043]FIG. 19 illustrates a protective nut with a crush lip.

[0044]FIG. 20 is a longitudinal section through threaded insert with aflare attachment.

[0045]FIG. 21 is a perspective view of a stimulator in combination witha flare nut.

[0046]FIG. 22 is a longitudinal section showing the flare nut with arubber boot.

[0047]FIG. 22A is a section showing tie interaction with the rubber bootof FIG. 22.

[0048]FIG. 23 is a top view of a disk-shaped miniature stimulator withelectrodes.

[0049]FIG. 24 is a side view of a disk-shaped miniature stimulator withelectrodes.

[0050]FIG. 25 illustrates a miniature stimulator annular electrode and asection through the annular nut.

[0051]FIG. 26 is an end view of the miniature stimulator with annularelectrodes.

[0052]FIG. 27 is an end view of the annular nut.

[0053]FIG. 28 is a longitudinal section through a miniature stimulatorwith annular electrodes and a section through the annular nut.

[0054]FIG. 29 illustrates an end view of a plug with wires.

[0055]FIG. 30 is a longitudinal cross-section through a plug with wiresinstalled in a hollow miniature stimulator.

[0056]FIG. 31 illustrates a perspective view of an electricallyconductive doorknob shaped electrode with spring clip connector andwire.

[0057]FIG. 32 is a perspective view of the electrically conductivedoorknob shaped electrode.

[0058]FIG. 33 is a perspective view of the spring clip connector.

[0059]FIG. 34 is a longitudinal section through the doorknob shapedconnector with a wire and rubber boot.

[0060]FIG. 35 is a longitudinal section through the doorknob shapedconnector with crimped connector a wire and rubber boot.

[0061]FIG. 36 is longitudinal section through the snap-on cap connectorwith rubber boot.

[0062]FIG. 37 is longitudinal section through the elongated snap-on capconnector with rubber boot.

[0063]FIG. 37A details the tooth interaction with the slip-on cap ofFIG. 37.

[0064]FIG. 38 is longitudinal section through the flat-bottomed slotconnector with rubber boot.

[0065]FIG. 39 is a perspective view of the flat-bottomed slot connector.

[0066]FIG. 40 is a perspective view of the flat-bottomed snap-on cap.

[0067]FIG. 41 is a cross-section of the flat-bottomed slot connector inthe engaged position.

[0068]FIG. 42 is a cross-section of the flat-bottomed slot snap-on capin the disengaged position.

[0069]FIG. 43 is a hand showing placement of an implantable miniaturedevice with a wire lead that carries electrical signals to a fingertip.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0070] An implantable miniature stimulator 2 is illustrated in FIG. 1.FIG. 43 represents a typical placement of the implantable miniaturestimulator 2 at a location that is remote from the site that is to bestimulated, in this case a fingertip, where an electrically conductivewire 38 carries the electrical signal to an electrode 39 at thestimulation site. Typical dimensions for this device are about 5 to 60mm in length and about 1 to 6 mm in diameter. (See, for example, U.S.Pat. Nos. 6,164,284, 6,185,452, and 6,208,894 which are incorporatedherein by reference in their entirety.) While element 2 is generallydescribed as a stimulator, it is recognized that the present inventionis equally applicable when element 2 is operable as a sensor or as astimulator and a sensor. Stimulator 2 includes insulating case 4, whichtypically is hollow and contains an electronics package and a powersource, such as a battery, capacitor, magnetic field to electricityconverter, and electrically conductive case ends 6, each of which has anelectrically conductive electrode 8 which conducts electrical signalsfrom a stimulator and/or to a sensor, depending upon the design andfunction of that particular miniature stimulator 2. Stimulator 2 mayhave at least one electrode, e.g., 2-8 or more, depending upon itsparticular design and function, although, for illustrative purposes,only two electrodes are shown in FIG. 1. Electrically conductiveelectrodes 8 are shown threaded in FIG. 1, although alternateembodiments are shown in other figures and are discussed herein.

[0071] Insulating case 4 contains the electronics, which may include abattery or other energy storage device and signal generating orreceiving circuitry and is made of an electrically insulating materialthat is capable of being hermetically sealed and that is alsobiocompatible, such as plastic or ceramic. The plastic may be epoxy,polycarbonate, or plexiglass. The ceramic may be alumina, glass,titania, zirconia, stabilized-zirconia, partially-stabilized zirconia,tetragonal zirconia, magnesia-stabilized zirconia, ceria-stabilizedzirconia, yttria-stabilized zirconia, or calcia-stabilized zirconia, andin a preferred embodiment, insulating case 4 is yttria-stabilizedzirconia, although other insulating materials may also be used. Theinsulating case 4 must be a material that is biocompatible as well ascapable of being hermetically sealed, to prevent permeation of bodilyfluids into the case.

[0072] The electrically conductive case end 6 is preferably abiocompatible, non-corrosive material, such as titanium or a titaniumalloy, although other metals such as platinum, iridium,platinum-iridium, stainless steel, tantalum, niobium, or zirconium maybe used. The preferred material is Ti-6 Al-4 V. An alternate preferredmaterial is platinum-iridium.

[0073] If any electrically conductive electrode is not being used whilethe stimulator is in the body, then the electrode may be insulated toprevent stimulation of nearby tissue. Protective nut 10 is either aninsulator or an electrically conductive conductor. If it is anelectrical conductor, then it is an extension electrode of electricallyconductive case 6. It is placed over the unused electrically conductiveelectrode 8 such that protective nut threaded hole 12 is tightly screwedonto threaded electrically conductive electrode 8. In a preferredembodiment, the threads on threaded electrically conductive electrode 8are 0-80 threads. In order to avoid growth of tissue into joints, suchas the joint formed between protective nut 10 and electricallyconductive case end 6, it is preferable that any gap be less than 7microns.

[0074] An alterative embodiment is illustrated in FIG. 2 where bayonetelectrode 14 is covered by protective nut 15 that contains bayonet mount16. Yet another embodiment of miniature stimulator 2 is illustrated inFIG. 3, where electrically conductive electrode 8 is now stud electrode21, a smooth stud, which has electrode through-hole 18 passing radiallythrough and intersecting with the longitudinal axis of stud electrode21. Stud protective nut 19 is placed onto stud electrode 21 such thatprotective nut mounting hole 20 fits over stud electrode 21 whileprotective nut through-hole 22 is aligned with electrode through-hole18. Protective nut through-hole 22 is positioned such that it passesradially through and intersects with the longitudinal axis of protectivenut 19 and such that nut 19 fits very snugly against electricallyconductive case end 6. Breakaway pin 24 is placed into protective nutthrough-hole 22 and into electrode through-hole 18. After alignment ofprotective nut 19 onto electrode 21 is complete, the protruding portionof breakaway pin 24 is broken off and discarded.

[0075] A preferred method of attaching an electrically conductive wire38 to a miniature stimulator 2 (see FIG. 1) is illustrated in FIGS. 4,5, and 6 wherein flare nut 26 is comprised of protective nut 28, whichcontains flare nut mounting hole 30. Threaded flare nut mounting hole 30is positioned over electrode 8 (see FIG. 1) and tightened by screwingonto the threads. Flare nut 26 also contains flare nut wire receptor 32which has flare 34 on its extension pointed away from protective nut 28.Because of the small diameter of wire used in this application, flare 34is provided for ease of placement of electrically conductive wire 38into flare 34. Offset through-hole 36 passes through flare nut wirereceptor 32 in a plane that is perpendicular to the longitudinal axis offlare nut 26. Offset through-hole 36 preferably does not intersect withthe longitudinal axis of nut 26, but is intentionally offset topenetrate wire insulator 41 (see FIG. 6) and to intersect with the outerdiameter of wire conductor 40. Thus when a pin, not illustrated, isplaced in offset through-hole 36, wire conductor 40 is contacted,creating an electrically conductive path between wire conductor 40 andprotective nut 28.

[0076] The cross-sectional view of FIG. 5 illustrates the offsetalignment of offset through-hole 36 with respect to the longitudinalaxis of flare nut wire receptor 32. Wire conductor 40 is intersected byoffset through-hole 36 such that wire insulator 41 will be penetratedand wire conductor 40 will be contacted by a pin inserted in offsetthrough-hole 36. Electrically conductive wire 38, shown in FIG. 6 iscomprised of wire conductor 40 within wire insulator 41. Alternately,wire insulator 41 may be stripped from an end portion of wire conductor40, to help insure good electrical contact between conductor 40 andflare nut wire receptor 32.

[0077] In a preferred embodiment, wire conductor 40 is a highlyconductive metal that is also benign in the body, such as MP35, althoughstainless steel or an alloy of platinum-iridium may also be used.Preferably, the wire has a diameter of approximately 0.003 inches. It iscontained in wire insulator 41 to electrically isolate it from the bodytissue and fluids and, in a preferred embodiment, wire insulator 41 isTeflon-coated silicone.

[0078] An alternate method of attaching an electrically conductive wire(not shown) to electrically conductive case end 6 is shown in FIG. 7,where an electrically conductive wire is attached to smooth studelectrode 21 by placing smooth protective nut 42 over stud electrode 21by aligning protective nut mounting hole 43 with stud electrode 21 andengaging them. Offset through-hole 44 is of a diameter that allows aninsulated wire to pass therethrough and it is aligned such that whensmooth protective nut 42 is pushed onto stud 21, the electricallyconductive wire is contacted and crushed, thereby making electricalcontact between the electrically conductive wire and stud electrode 21.A cross-sectional view through protective nut 42, illustrated in FIG. 8,shows the alignment of offset through-hole 44 with respect to protectivenut mounting hole 43. Smooth protective nut 42 is retained on stud 21 byvirtue of the frictional force generated by a crushed wire present inoffset through-hole 44 as protective nut 42 is placed on stud electrode21.

[0079] In an alternate embodiment, shown in FIG. 9, miniature stimulator2 has at one end threaded electrically conductive electrode 8 and at theother end threaded electrode hole 46. Alternate embodiments containvarious combinations of electrically conductive electrodes 8 andelectrode holes 46. FIG. 9 illustrates one such combination ofdissimilar electrodes. As discussed previously, if an electrode isunused, then it must be covered and protected to prevent tissue damageor undesirable tissue growth into the stimulator. If threaded electrodehole 46 is unused, then it is filled with electrode plug 48, which isscrewed tightly into hole 46, as illustrated in FIG. 10.

[0080] A further method of attaching an electrically conductive wire 38(not illustrated) to electrically conductive case end 6 is illustratedin FIG. 11, where threaded electrode hole 46 mates with smooth nut 52 byinserting threaded insert 50 into threaded electrode hole 46. As nut 52is tightened, an electrically conductive wire, not illustrated, that haspreviously been inserted in smooth nut through-hole 54 is crushedbetween electrically conductive case end 6 and nut crush lip 56, therebymaking contact between the electrically conductive wire and electricallyconductive case end 6. Smooth nut through-hole 54 retains the wire inposition and assures that the wire is secured in place until smooth nut52 is fully tightened.

[0081] Illustrated in FIG. 12 is an alternate embodiment of a method ofattaching an electrically conductive wire to a miniature stimulator 2,wherein electrically conductive case end 6 has threaded electricallyconductive electrode 8 attached thereto. Electrically conductiveelectrode 8 contains electrode through-hole 18 located proximate toelectrically conductive case end 6. Protective nut 10 is attached tothreaded electrically conductive electrode 8 by screwing electricallyconductive electrode 8 into protective nut threaded hole 12. Anelectrically conductive wire, not shown, is held in place by placing itthrough electrode through-hole 18. The wire makes electrical contactwith electrically conductive case end 6 by virtue of being crushedbetween electrically conductive case end 6 and protective nut 10 by nutcrush lip 56.

[0082] A further embodiment of methods to attach an electricallyconductive wire (not illustrated) to assure electrical conductivitybetween the electrically conductive wire and the electrically conductivecase end 6 is illustrated in FIG. 13, where spade clip 58, which isattached to an electrically conductive wire (not illustrated), issecuredly fastened between protective nut 10 and electrically conductivecase end 6.

[0083] Spade clip 58 is shown in FIG. 14 with tab 60 configured toattach to electrically conductive wire 38. Electrically conductive wire38, is placed in tab 60 with wire insulator 41 stripped from an endportion of the electrically conductive wire 38, thereby exposing wireconductor 40 for electrical contact with tab 60. Tab 60 is wrappedaround electrically conductive wire 38 so as to assure that electricallyconductive wire 38 is securely attached to spade clip 58 by wrapped tab60, which has crimp 70, as shown in FIG. 15.

[0084]FIG. 15 illustrates spade clip 58 with electrically conductivewire 38 attached to spade clip 58 and retained by crimp 70. Opening 62in spade clip 58 is configured to approximate the diameter ofelectrically conductive electrode 8 (see FIG. 13) such that spade clip58 fits over electrically conductive electrode 8 (not illustrated). In apreferred embodiment, tab 60 and electrically conductive wire 38 areoriented at a right angle to spade clip 58, thus assuring thatelectrically conductive wire 38 is parallel to the longitudinal axis ofminiature stimulator 2, thereby minimizing stresses in the wire. FIGS.15A and 15B illustrate detailed alternate crimp 70 attachment methods ofsecuredly fastening wire conductor 40 to spade clip 58.

[0085] An alternate embodiment, illustrated by cross-sectional view inFIG. 16, has a wire (not shown) placed through smooth nut through-hole54, which is located proximate to smooth nut 52. As smooth nut 52 istightened into threaded electrode hole 46 by inserting threaded insert50 into threaded electrode hole 46, the wire is crushed between endcrush lip 72 and cap 52, thereby making electrical contact between thewire and electrically conductive case end 6. The difference between themethod of wire attachment illustrated in FIG. 11 and that shown by FIG.16 is the relocation of nut crush lip 56 from the protective nut 10 ofFIG. 11 to electrically conductive case end 6, as end crush lip 72 inFIG. 16.

[0086] Illustrated in FIGS. 18 and 19 is a further embodiment of amethod of attaching an electrically conductive wire (not shown) tominiature stimulator 2, wherein smooth electrode 76 contains no threadsand also has offset electrode through-hole 75, which is aligned to liein a plane that is perpendicular to the longitudinal axis of miniaturestimulator 2 to intersect with the outer diameter of wire conductor 38,such that when a pin (not shown) is placed in through-hole 75, it willcontact wire conductor 40, either by penetrating wire insulator 41 or bycontacting the wire conductor 40 directly, if wire insulator 41 has beenstripped from that area. Protective nut 10, shown in FIG. 19,illustrates nut crush lip 56, and also illustrates offset protective nutmounting hole 77, which aligns with offset electrode through-hole 75,thereby allowing a pin (not shown) to pass through both offsetprotective nut mounting hole 77 and offset electrode through-hole 75.

[0087] A further embodiment, illustrated by cross-sectional view in FIG.20, is similar to the embodiment presented in FIG. 4, but withelectrically conductive case end 6 having threaded electrode hole 46 inplace of flare nut mounting hole 30. Threaded insert 50 is screwed intothreaded electrode hole 46, thereby securing protective nut 28 toelectrically conductive case end 6. An electrical connection betweenelectrically conductive wire 38 is made by stripping wire insulator 41from the end of wire 38 thus exposing wire conductor 40. Conductor 40 isinserted into flare nut wire receptor 32 using flare 34 as a guide. Wireinsulator 41 is stripped such that, when wire conductor 40 is insertedfully into flare nut wire receptor 32, wire insulator 41 extendsapproximately one-quarter of the length of receptor 32 into receptor 32.Wire 38 is securedly attached inside receptor 32 by crimping receptor 32to wire conductor 40.

[0088] An alternate method of attaching protective nut 28 to smooth studelectrode 21 is illustrated in FIG. 21. While the preferred method ofattaching the two components is by screwing them together, asillustrated in FIGS. 4 and 20, in the instant embodiment, electricallyconductive case end 6 has stud electrode 21 attached thereto, which hasno threads. Protective nut 28 slips snugly over stud electrode 21 untilelectrically conductive case end 6 is located touching adjoiningprotective nut 28. As previously illustrated in FIG. 20 and as discussedabove, wire 38 and its conductor 40 and wire insulator 41 are securelyfitted inside flare nut wire receptor 32 by using flare 34 as a guide.Electrically conductive wire 38 is secured by crimping flare nut wirereceptor 32 onto wire conductor 40 (see FIG. 21). Protective nut 28 issecured to stud electrode 21 by placing C-clip 74 (see FIG. 17) overprotective nut 28 such that protective nut 28 is partially deformed,thereby creating a secure attachment between stud electrode 21 andprotective nut 28.

[0089] The preferred method of assuring electrical insulation betweenelectrically conductive case end 6, electrically conductive electrode 8,protective nut 28, and wire 38, as illustrated in FIG. 22, is to coverthe electrically conductive case end 6 and other parts with rubber boot82. Rubber boot 82 is made of a flexible insulating material that isbiocompatible, such as silicone. Its purpose is to provide electricalinsulation such that stray electrical signals do not pass betweensurrounding tissue and any electrically conductive part of the device.Rubber boot 82 is secured to the device, preferably by tying it in placewith ties 84. A sufficient number of ties 84 are placed by the surgeonto assure that that the rubber boot 82 will not move. It is preferredthat at least one tie 84 and, preferably two or more ties 84, be placedon rubber boot 82 to secure rubber boot 82 to insulating case 4, so asto electrically insulate electrically conductive case end 6 from theliving tissue. FIG. 22A illustrates a typical tie 84 interacting withrubber boot 82, so as to establish and maintain a hermetic seal.Alternate methods of attaching rubber boot 82 include the use of ridgesinside rubber boot 82, clamps over rubber boot 82, silicone adhesiveinside rubber boot 82, ridges on the outside of insulating case 4, amale notch with matching female indentation forming an O-ring seal, andthe tight fit of rubber boot 82 over the device, either with or withoutinternal ridges.

[0090] An alternate configuration to miniature stimulator 2, previouslyillustrated in FIG. 1, is miniature disk stimulator 86, which isillustrated in FIGS. 23 and 24. Disk 88 is preferably comprised ofinsulating material having at least one electrically conductiveelectrode 90. Two electrodes are illustrated in FIGS. 23 and 24, butalternate arrangements have at least one, e.g., 1 to 8 or more,electrodes. Electrode 90 is hermetically bonded to disk 88. Electrode 90can be one or more tabs as shown in FIG. 23, or it can be one or moreflush electrodes (not illustrated) that are mounted on the surface ofdisk 88. While the tabs 90 that are illustrated in FIGS. 23 and 24project from the surface of the insulating disk 88, the tabs 90 canequally well not project from the surface of insulating disk 88 and maybe contiguous with the surface such that they do not project above thesurface. The methods of connecting a wire to the miniature stimulatorthat have been previously discussed are equally applicable to miniaturedisk stimulator 86, as well as to other configurations. The dimensionsof disk 88 are about 5 to 40 mm diameter and about 1 to 6 mm thick.Electrically conductive electrode 90 is preferably made of an electricalconductor that is biocompatible and corrosion resistant, such asplatinum, iridium, platinum-iridium, tantalum, titanium or a titaniumalloy, stainless steel, niobium, or zirconium. Disk 88 is made of anelectrical insulator that is biocompatible, such as ceramic, glass, orplastic.

[0091]FIG. 25 illustrates an alternate annular electrode arrangement onthe end of miniature stimulator 2. At least one annular electrode may beused, e.g., four annular electrodes 92 are illustrated in FIG. 25. Eachannular electrode 92 is capable of carrying an independent electricalsignal and is electrically isolated from the other electrodes. Thesignal from or to stimulator 2 passes along electrically conductivewires 38, where each electrically conductive wire 38 carries anindependent signal and is electrically isolated from the others. Eachelectrically conductive wire 38 corresponds with and is connected to oneannular electrode 92 by means of its connecting to toroidal spring 98.Alternatively, toroidal spring 98 may be a semi-circular spring. Annularcap 94 contains toroidal springs 98. Electrically conductive wires 38pass through holes in the end of cap 94. The internal diameter ofannular cap opening 96 approximates but is slightly larger than theouter diameter of stimulator 2. To make a connection between annularelectrode 92 and toroidal spring 98, annular cap 94 is pushed in alongitudinal direction along the axis of stimulator 2 until it is fullyengaged in a position such that electrical contact is made betweenannular electrode 92 and a corresponding toroidal spring 98. Eachtoroidal spring 98 is preferably retained inside annular cap 94 by anannular recession inside annular cap 94 such that during engagement ofstimulator 2 with annular cap 94, the toroidal spring 98 is forced intothe recession, thereby allowing room for smooth engagement of the parts.The alignment of toroidal spring 98 and annular electrode 92 is suchthat each toroidal spring 98 contacts only one corresponding annularelectrode 92.

[0092]FIG. 26 illustrates the case end 100 of stimulator 2 and FIG. 27illustrates the end view of annular cap 94. A cross-sectional view ofannular electrode 92 is illustrated in FIG. 28.

[0093] Another embodiment for making an electrical connection tominiature stimulator 2 is illustrated in FIGS. 29 and 30. FIG. 29illustrates an end view of electrode plug 104 (see FIG. 30) showing fourelectrically conductive wires 38 passing into the center of electrodeplug 104 through potting material 106. The potting material provides asecure, hermetic seal for wires 38 to pass into miniature stimulatorcore 102, as illustrated in FIG. 30.

[0094]FIG. 30 illustrates a longitudinal view in cross-section ofminiature stimulator 2 comprising insulating case 4, electricallyconductive case end 6, electrode plug 104, and potting material 106.Electrode plug 104 is made of a biocompatible material such as titaniumand is attached by weld 105 to electrically conductive case end 6,thereby forming a hermetic seal.

[0095] Another embodiment for making an electrical connection to aminiature stimulator 2 is illustrated in FIG. 31 where doorknobelectrode 108 is intimately attached to electrically conductive case end6. The doorknob electrode is made of a material that is electricallyconductive and biocompatible, such as titanium. Spring clip 110 ispreferably a clip made of titanium which has two or more, and preferablythree or four prongs. Wire insulator 41 is stripped from the end of wire38 thereby exposing wire conductor 40. Wire conductor 40 is preferablyattached to spring clip 110 by strain relief weld 112. Strain reliefweld 112 helps to relieve strain in wire conductor 40 by virtue of beingoriented perpendicular to the longitudinal axis of miniature stimulator2. Further strain relief is provided in wire conductor 40 by virtue ofit being tightly coiled inside wire insulator 41 thereby forming wirestrain relief 114. The inside of wire insulator 41 is fill material 115,which is preferably soft silicone, to minimize infiltration of bodyfluids and other tissue inside wire 38.

[0096] A perspective view of doorknob electrode 108, showing its endattached to electrically conductive case end 6, is illustrated in FIG.32. FIG. 33 illustrates a perspective view of spring clip 110 showingthe four prongs that slip over doorknob electrode 108 to form anelectrical connection.

[0097]FIG. 34 illustrates spring clip 110 together with electricallyconductive wire 38, which in turn is attached by strain relief weld 112to wire conductor 40. Spring clip 110 is shown in its attached positionon doorknob electrode 108. Rubber boot 82 is securely fastened to thedevice with ties 84 to completely cover electrically conductive case end6, doorknob electrode 108, wire conductor 40 and a portion of wireinsulator 41, thus electrically insulating the body tissue fromelectrical signals.

[0098] An alternate embodiment is presented in FIG. 35, which is similarto the connection device presented in FIG. 34 except that connectorcrimp 118, which is selected from the group of biocompatible materials,and is preferably platinum metal, is placed over the end of electricallyconductive wire 38 so as to cover a portion of wire insulator 41 andstripped wire conductor 40. Connector crimp 118 is attached toelectrically conductive wire 38 by crimping it onto wire 38.

[0099] A preferred embodiment is shown in FIG. 36 in which slip-on cap122 has a slightly larger internal diameter of a portion of slip-on cap122 such that it slips over the outer diameter of insulating case 4.Snap-on cap 120 has at least one flexible member 130 having a tooth 135on each flexible member 130. Tooth 135 engages the edge of electricallyconductive slip-on cap 122, as illustrated in FIG. 37A, and holdssnap-on cap 120 tightly in place. Electrical conductivity is achievedbetween electrically conductive wire 38 and electrically conductiveslip-on cap 122 by spring disk 125 holding enlarged end of wire 140tightly in contact with electrically conductive slip-on cap 122 whensnap-on cap 120 is in place. Rubber boot 82 provides electricalinsulation by covering electrically conductive slip-on cap 122, snap-oncap 120, and a portion of electrically conductive wire 38.

[0100] An alternate embodiment is shown in FIG. 37 in which snap-on cap120 is elongated and slotted on the end opposite tooth 135. When slottedelongated end 123 is squeezed, flexible members 130 are levered outwardand tooth 135 is thereby disengaged from the edge of slip-on cap 122.FIG. 37A illustrates the interaction of tooth 135 with slip-on cap 122such that snap-on cap 120 is securedly fastened to slip-on cap 122.

[0101] An alternate embodiment is shown in FIG. 38 in which electricallyconductive case end 6 contains at least one angled flat 150 to allowrotatable cap tooth 136 of rotatable cap 133 to slide smoothly onto theend of electrically conductive case end 6 and to facilitate alignment ofrotatable cap tooth 136 with flat-bottomed slot 145. Electricallyconductive case end 6 has at least one flat-bottomed slot 145 thatengages rotatable cap tooth 136 of rotatable cap 133 to retain rotatablecap 133 on electrically conductive case end 6. When rotatable cap 133 isrotated about its longitudinal axis by about 30° to 90°, rotatable captooth 136 is rotatably moved out of flat-bottomed slot 145, therebyallowing rotatable cap 133 to be removed. These elements are shown inthe perspective views of FIGS. 39 and 40, the angled flat 150 isindicated to facilitate placement of rotatable cap 133 onto electricallyconductive case end 6 in order to engage rotatable cap tooth 136 withflat-bottomed slot 145.

[0102] A cross-sectional view, through flat-bottomed slot 145 andperpendicular to the longitudinal axis, is presented in FIGS. 41 and 42.The view of FIG. 41 indicates the position when rotatable cap 133 is inposition to engage rotatable cap tooth 136 with flat-bottomed slot 145.The view of FIG. 42 indicates the same cross-sectional view as in FIG.41 but rotatable cap 133 has been rotated 90° from the positionillustrated in FIG. 41 to disengage rotatable cap tooth 136 fromflat-bottomed slot 145 thereby allowing removal of rotatable cap 133.

[0103] These various embodiments are of devices and methods forconnecting an electrically conductive wire to a miniature, implantablestimulator in order to efficiently transmit or receive an electricalsignal that is associated with the implantable stimulator.

[0104] Obviously, these methods of attaching a wire to a miniatureimplantable stimulator can be used in permutations and combinations notspecifically discussed herein. Many modifications and variations of thepresent invention are possible in light of the above teachings. It istherefore to be understood that, within the scope of the appendedclaims, the invention may be practiced otherwise than as specificallydescribed.

What is claimed is:
 1. An improved structure for communicatingelectrical signals between living tissue and an implantable miniaturedevice configured for monitoring and/or affecting body parameters,wherein said miniature device has an axial dimension of less than about60 mm and a lateral dimension of less than about 6 mm and at least oneend of said implantable device includes at least one electricallyconductive surface coupled to electrical circuitry contained within,said improvement comprising: at least one electrically conductive caseend comprised of at least one doorknob electrode for communicatingelectrical signals between the living tissue and said implantableminiature device by means of at least one electrically conductive wirehaving a first end configured for electrical coupling to a selectedportion of the living tissue and a second end configured for coupling tosaid implantable miniature device; at least one electrically conductiveconnector for attaching said at least one electrically conductive wireto said at least one doorknob electrode; and an insulating rubber bootsurrounding said at least one electrically conductive case end, said atleast one electrically conductive electrode, and said at least oneelectrically conductive connector.
 2. The improved structure of claim 1wherein said at least one electrically conductive case end is a materialselected from the group consisting of titanium, titanium alloy,platinum, iridium, platinum-iridium, zirconium, niobium, stainlesssteel, and tantalum.
 3. The improved structure of claim 1 wherein saidat least one electrically conductive case end is comprised of Ti-6 Al-4V.
 4. The improved structure of claim 1 wherein said at least onedoorknob electrode is a material selected from the group consisting oftitanium, titanium alloy, platinum, iridium, platinum-iridium, stainlesssteel, tantalum and niobium.
 5. The improved structure of claim 1wherein said insulating rubber boot is comprised of silicone.
 6. Theimproved structure of claim 1 wherein said at least one electricallyconductive connector comprises a spring clip.
 7. The improved structureof claim 6 wherein said spring clip has at least one prong for graspingsaid doorknob electrode.
 8. The improved structure of claim 6 whereinsaid spring clip is a material selected from the group consisting oftitanium, titanium alloy, platinum, iridium, platinum-iridium, stainlesssteel, tantalum and niobium.
 9. The improved structure of claim 1wherein said at least one electrically conductive connector comprises astructure having at least one prong for grasping said doorknobelectrode.
 10. A method of communicating electrical signals betweenliving tissue and an implantable miniature device configured formonitoring and/or affecting body parameters, comprising: snapping anelectrically conductive connector over a doorknob electrode that isattached to an electrically conductive surface on an implantableminiature device; attaching an electrically conductive wire having afirst end configured for electrical coupling to a selected portion ofthe living tissue and a second end configured for coupling to saiddoorknob electrode; implanting said first end of said electricallyconductive wire where it is in contact with the living tissue; andimplanting said miniature implantable device in the living tissue atsome distance from said first end of said electrically conductive wire.11. A spring clip connector adapted to receive a doorknob electrode forcommunicating electrical signals between living tissue and animplantable miniature device configured for monitoring and/or affectingbody parameters, comprising: at least one prong for grasping saiddoorknob electrode, a connection to at least one electrically conductivewire having a first end configured for electrical coupling to a selectedportion of the living tissue and a second end configured for attachmentto said spring clip, wherein said spring clip is a biocompatiblematerial.
 12. The spring clip connector of claim 11 wherein saidbiocompatible material is selected from the group consisting oftitanium, titanium alloy, platinum, iridium, platinum-iridium, stainlesssteel, tantalum and niobium.
 13. An improved structure for communicatingelectrical signals between living tissue and an implantable miniaturedevice configured for monitoring and/or affecting body parameters,wherein said miniature device has an axial dimension of less than about60 mm and a lateral dimension of less than about 6 mm and at least oneend of said implantable device includes at least one electricallyconductive surface coupled to electrical circuitry contained within,said improvement comprising: at least one electrically conductive caseend comprised of at least one doorknob electrode for communicatingelectrical signals between the living tissue and said implantableminiature device by means of at least one electrically conductive wirehaving a first end configured for electrical coupling to a selectedportion of the living tissue and a second end configured for coupling tosaid implantable miniature device; a means for attaching said at leastone electrically conductive wire to said at least one doorknobelectrode, and an insulating rubber boot surrounding said at least oneelectrically conductive case end, said at least one electricallyconductive electrode, and said at least one electrically conductiveconnector.
 14. The improved structure of claim 13 wherein said means forattaching said at least one electrically conductive wire to said atleast one doorknob electrode comprises a spring clip.
 15. The improvedstructure of claim 14 wherein said spring clip is a material selectedfrom the group consisting of titanium, titanium alloy, platinum,iridium, platinum-iridium, stainless steel, tantalum and niobium. 16.The improved structure of claim 14 wherein said spring clip has at leastone prong for grasping said doorknob electrode.
 17. The improvedstructure of claim 13 wherein said at least one electrically conductivecase end is a material selected from the group consisting of titanium,titanium alloy, platinum, iridium, platinum-iridium, zirconium, niobium,stainless steel, and tantalum.
 18. The improved structure of claim 13wherein said at least one electrically conductive case end is comprisedof Ti-6 Al-4 V.
 19. The improved structure of claim 13 wherein said atleast one doorknob electrode is a material selected from the groupconsisting of titanium, titanium alloy, platinum, iridium,platinum-iridium, stainless steel, tantalum and niobium.
 20. Theimproved structure of claim 13 wherein said insulating rubber boot iscomprised of silicone.